JPH0139061B2 - - Google Patents

Abstract

PURPOSE:To perform the detection suited for visual feeling with less space by obtaining a distributed light pattern equal and resembling to a distributed light pattern in a short distance by the use of an optical lens, and measuring and processing the luminous intensity of each point thereof. CONSTITUTION:The distributed light similarly reduced, for example, 10m distributed light is obtained on a plane installed with a photosensor array Sm by a headlamp HL and a condenser lens L. The photosensor array Sm detects the quantity of light of them positions on a straight line and the output thereof is inputted to a microcomputer MPU. The microcomputer MPU consists of a storage circuit MEM, an input-output circuit IO and a central processing unit CPU, calculates orientation by operation and displays the results thereof in a display panel DP.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical axis detection device for an automobile headlamp.

In order to ensure forward visibility and avoid dazzling oncoming vehicles, automobile headlights are regulated in terms of direction, up and down, left and right, and must be properly adjusted and installed within these limits. It won't happen.

As an example, as shown in Figure 1, the current headlight tester that inspects the irradiation direction of headlights uses two pairs of light-receiving elements, upper and lower and left and right. A method is adopted in which the optical axis, which is the axis of the irradiation direction, is detected by inserting a point where the luminous intensity of the pair is balanced. In the figure, HL is a headlamp, T is a headlight tester, J is a pair of left and right balance detection sensors, and K is a pair of vertical balance detection sensors.

However, with this method, JIS and
It is possible to detect the optical axis of a headlight that has a light distribution pattern like a running beam regulated by SAE, but it is possible to detect the optical axis of a headlight that has a light distribution pattern like a driving beam regulated by SAE, but it is also possible to detect a passing beam of a headlight according to JIS or SAE standards or a mismatch of headlights according to European standards. It cannot be used in cases such as beams.

However, in recent years, in order to improve safety and increase the frequency of use, headlights have been designed with more emphasis on passing beams than on driving beams, and at the same time, optical axis adjustment (aiming) has become more important when installing headlights. is becoming increasingly important. Additionally, headlights are required to be able to see obstacles 100 meters ahead. In JIS, headlights are regulated by a light distribution pattern projected on a screen 10 meters in front of the vehicle. Headlamps are therefore designed to meet this requirement.

By the way, since a headlight is not a point light source but a surface light source with a certain area, it is important to avoid the light distribution pattern projected on the screen from differing depending on the distance from the headlight, especially at short distances. I can't. However, the current headlight tester is a method that performs measurements at a relatively short distance (3 meters) from the headlight, due to the fact that it is practically difficult to widely install measurement equipment in a vehicle inspection area. Therefore, the change in light distribution caused by this difference in distance, that is, the difference between 3 meters and 10 meters, is a value that cannot be ignored.

Furthermore, the direction of irradiation of headlights is determined by human visual perception, and current headlights and
Since the tester physically measures the amount of light,
This may end up measuring parts, ranges, contrast, etc. that cannot be perceived by humans, which may lead to results that are contrary to the purpose of the measurement.

The present invention has been made in view of the above points and provides a novel optical axis detection device for an automobile headlamp that has been made to solve such problems. For example, a reduced light distribution pattern that is equally similar to a 10 meter light distribution pattern can be obtained at a short distance of 1 meter, and a light sensor array in which multiple light intensity sensors are arranged at regular intervals on a straight line can be used to create a reduced light distribution pattern. By moving it relative to the pattern, the light intensity at many points is measured over the entire surface of the reduced light distribution pattern, and the light intensity data obtained from this measurement is processed by a microcomputer. Accordingly, the irradiation direction of the headlight is determined and its optical axis is detected.

In addition to the above-mentioned first invention, the second invention uses a switch means to notify the microcomputer of the start of its processing operation, the left and right side of the headlight, and the height from the ground, and then performs measurement. By processing the light amount data obtained by using a microcomputer, the irradiation direction of the headlight is determined and its optical axis is detected.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

First, in order to facilitate understanding of the present invention, means for reducing a 10 meter light distribution pattern to a short distance will be explained with reference to FIG. In the figure, the center of the condensing lens L is placed on the lamp axis O-O' of the headlamp HL, and a virtual screen on which the condensing lens L and the reduced light distribution are reflected relative to the lamp axis O-O'
Screen SC ₁ and SC ₂ with 10 meter light distribution
When installed vertically, if there is no condenser lens L and virtual screen SC ₁ , the headlamp HL
By inserting _the condensing lens L, the light distribution projected on _the screen SC ₂ placed 10 meters from It will be done. At this time, there is a predetermined correlation between the distances b ₁ and b ₂ and the focal length F of the condenser lens L or the reduction rate m of the light distribution, and this can be changed depending on the design specifications. can do. In addition, in the figure, P indicates the center of the condensing lens L.

By collecting light amount data from the reduced light distribution pattern projected in this way, measurements equivalent to 10 meter light distribution measurements can be made at short distances.

Next, a method of sampling light quantity data of the reduced light distribution pattern will be explained. First, in order to have wide versatility for various types of light distribution and to realize processing similar to the visual sense, we developed a method that collects light amount data for small light distribution patterns over a wide range and in small pieces. Use. The light amount data of the reduced light distribution pattern projected on the virtual screen SC ₁ in FIG. 2 is collected in the following manner. In FIG. 3, which shows an example, H is a horizontal line and V is a vertical line, which are orthogonal to the lamp axis on the plane of the virtual screen _SC1 . However, the planes of the virtual screen SC ₁ , the horizontal line H, and the vertical line V are in the same plane. Further, Sm is a light sensor array in which m light quantity sensors are arranged at regular intervals on a straight line. This optical sensor array Sm is connected to the lamp axis O-
The virtual screen SC 1 is set up parallel to the vertical line V on the plane of the virtual screen SC ₁ , which is orthogonal to O' (see Figure 2) at the point O ₁ , and while it is moved in parallel from point A to point B along the horizontal line H, there is a certain By collecting light amount data n times at intervals, the interior of rectangle ABCD is arranged in a grid pattern of m×
It can be divided into n pieces of light amount data and collected.

That is, by scanning the optical sensor array Sm up to n positions, m×n pieces of light amount data within the rectangle ABCD are sampled. By employing such a sampling method, it is advantageous in terms of cost, accuracy, etc., compared to, for example, the case where the following sampling method is employed. That is, as another sampling method, m x n individual light quantity sensors are fixedly installed in a matrix at m x n positions on the virtual screen SC ₁ in FIG.
One possible method is to sample the light intensity data within the range (see figure). However, if such a sampling method is adopted, it is possible to omit the drive unit for moving the optical sensor array Sm, but the output from the light amount sensor (which will be described later) (the current and voltage change depending on the amount of light, i.e. m×n amplifiers are required to amplify the light intensity signal (obtained by photoelectric conversion). In other words, when such a sampling method is adopted, compared to using an array of optical sensors, more light amount sensors are required, and accordingly, more amplifiers are required. On the other hand, the method of moving the optical sensor array is simplified by reducing the number of components such as the light amount sensor and the amplifier, which promotes total cost reduction. Also,
Since the number of light amount sensors is small, variations in photoelectric conversion characteristics among the light amount sensors are small, and the detection accuracy of the optical axis, which will be described later, is improved.

Now, the present invention is implemented as follows. FIG. 4 is a block diagram showing the basic configuration of an embodiment of an optical axis detection device for an automobile headlamp according to the present invention. In the figure, HL is a headlamp, and L is a condensing lens, through which the optical sensor array Sm is installed. On the HV plane, a light distribution pattern that is similar to the 10 meter light distribution can be obtained. This light sensor array Sm includes m light amount sensors s ₁ ,
s ₂ ...s _n are arranged at regular intervals on a straight line, and each sensor can capture the amount of light at m locations on the straight line.

LA is an optical amplifier that amplifies the output (light amount signal) of the optical sensor array Sm, and is composed of m independent amplifiers LA ₁ , LA ₂ ... LAm for each light amount sensor s ₁ , s ₂ ...s _n . There is. SCN is a scanning section, and this scanning section SCN has a function to time-divide m amplified light intensity signals sent out from the optical amplifier LA and send them to the analog-to-digital converter AD, and this time-division operation is performed by the microcomputer MPU. It is configured to be controlled by commands from. The analog-digital converter AD has the function of converting the analog quantity sent from the scanning unit SCN into a digital quantity.
This analog-digital converter AD is also configured to be controlled by instructions from the microcomputer MPU.

DRV is a drive unit for moving the optical sensor array Sm as shown in FIG. 3, and is configured to operate in response to instructions from the microcomputer MPU. SW is a group of switches for providing information on the operation of the device, and this switch group SW includes a light distribution measurement start switch SSW and a car headlamp.
It consists of a switch RLSW that informs the microcomputer MPU of the left and right side of the HL, and a switch HSW that informs the microcomputer MPU of the height of the headlamp HL from the ground. Relevant at the time. The microcomputer MPU includes a memory circuit MEM that stores programs and light amount data for executing the operation of the optical axis detection device according to the present invention, an input/output circuit IO that transmits data and instructions to the outside, and their It consists of a central processing unit CUP that is in charge of control.

DP is a display panel that displays the results after light distribution measurement. For example, the luminous intensity of the high-luminosity band of the reduced light distribution pattern, the horizontal angle and vertical angle of the optical axis or the edge of the high-luminosity band, etc. are displayed with digital numbers or a pointer meter, and these 3
The device is configured to display the pass/fail results of comparing each value with the standard value using a lamp.

Next, the operation of the embodiment shown in FIG. 4 will be explained with reference to FIGS. 2 and 3. First, to aim (optical axis adjustment) the headlamp HL, first align the device so that the lamp axis O-O' and the device axis P- _O1 shown in Fig. 2 are in the same straight line, and then adjust the headlamp HL. Keep HL on. After this, measurement is started by pressing the light distribution measurement start switch (start switch) SSW in Fig. 4, the collected light amount data is stored in the memory circuit MEM in the microcomputer MPU, and processing that suits the purpose is performed. After getting used to it, display the result in the panel
Display on DP.

Next, the means by which the microcomputer MPU stores the light quantity data of the reduced light distribution pattern will be explained. First, when the start switch SSW is pressed,
The optical sensor array Sm moves to the position on sides A and B shown in FIG. 3 and stops. Here, the light amount sensor
The amount of light captured by s ₁ , s ₂ ...s _n is determined by the light amount sensor s ₁ , s ₂ ...s _n
Amplifiers LA ₁ , LA ₂ ...LAm corresponding to each of
Each signal is converted into a light amount signal. These light intensity signals are sequentially switched from the 1st to the mth by the operation of the scanning unit SCN controlled by the command α from the microcomputer MPU, and each time they are switched to the analog signal in response to the command β from the microcomputer MPU. It becomes a digital quantity in the digital converter AD, and is sequentially stored in the memory circuit MEM in the microcomputer MPU.

In this way, when m pieces of light intensity data have been collected at positions A and B on sides A and B, the microcomputer MPU again sends the command γ to the drive unit DRV to move the optical sensor array Sm to the position . ,
After stopping at the position, m pieces of light amount data are stored using the method described above.

This series of operations is performed n times, and the optical sensor array Sm
When reaching the position n shown in FIG. 3, the memory circuit MEM can store n×m pieces of total light amount data.

Next, based on the light intensity data collected as described above, the microcomputer MPU executes a program to calculate the direction angle of the optical axis and the edge of the high luminosity band, and calculates the reference value pre-stored in the memory circuit MEM. Compare with the standard values specified by the switches HSW and RLSW, and display the results on the display panel DP. Therefore, by looking at the displayed values and judgment lamps on the display panel DP, the measurer can know the measurement results, including pass/fail depending on the mounting position of the headlamp HL, at a glance.

Next, an example of a method of processing light amount data will be explained. Here, how to determine the optical axis of the traveling beam and how to calculate the optical axis direction angle will be explained using FIG. 5. In the figure, W indicates a reduced light distribution pattern of the headlamp HL on the HV plane of horizontal line H and vertical line V, and rectangle ABCD indicates the range of light quantity data stored in the microcomputer MPU. The straight line O-O ₁ -O' indicates the lamp axis. First, a reduced light distribution pattern W is projected on the HV plane, and the light amount data within the rectangle ABCD has already been stored. From this light amount data, a point M having the highest luminous intensity is found, and an isoluminous curve N having a value of n percent of this maximum luminous intensity is drawn. This isoluminance curve N becomes a certain luminous intensity band whose optical axis can be determined, its geometric center O ₂ is determined, and O-O ₂ is determined as the optical axis. The optical axis O--O ₂ determined in this way matches human visual perception.
Next, how the optical axis O- _O2 is inclined with respect to the lamp axis O- _O1 will be expressed as an angle with respect to the lamp axis O- _O1 . This representation is done as follows.

That is, from the relational expression between the reduction rate and distance determined in FIG. 2, the distance between the sensors on the virtual screen _SC1 on which the reduced light distribution pattern is projected is replaced by an angle using the calculation expression. Therefore, in FIG. 3, since the light sensor array Sm has the light quantity sensors arranged at a certain distance on a straight line, each point of the light quantity sensors 1...m at positions ~n of the light sensor array Sm is the lamp axis O-O ₁ -
It is determined by the angle with respect to O′. Therefore, all m×n measurement points are given by angles with the lamp axis O-O ₁ -O'. Since the m×n measurement light amount data are stored in the storage circuit MEM, the aforementioned geometrical center _O2 is calculated by the microcomputer MPU and expressed as an angle, and the optical axis O-- It is possible to detect which direction _O2 is tilted with respect to the lamp axis O- _O1 .

As is clear from the above description, according to the first invention of the present application, a reduced light distribution pattern is created by moving a light sensor array in which a plurality of light amount sensors are arranged at regular intervals on a straight line. It is possible to collect light intensity data at many points over the entire surface, and compared to methods such as collecting light intensity data of a reduced light distribution pattern using light intensity sensors arranged in a matrix,
The number of component parts such as a light amount sensor and an amplifier is reduced, and simplification is achieved, which promotes total cost reduction. Furthermore, since there are fewer light quantity sensors, variations in photoelectric conversion characteristics among the light quantity sensors are small, and optical axis detection accuracy is improved, which is extremely effective in practical use. Furthermore, JIS,
The irradiation direction can be determined without depending on the SAE or European light distribution pattern, or whether it is a driving beam or a passing beam, and it is also possible to measure light distribution at a short distance of 10 meters from the headlight. Since measurements can be made, there are no problems due to distance from the headlight, and excellent effects such as not requiring a large space for measurement equipment can be achieved. In addition, since the system uses a microcomputer to process a large amount of light distribution data covering a wide range of light distribution, it is extremely effective in that it is possible to make judgments that are compatible with visual perception. The disadvantages of this type of device can be eliminated.

Further, according to the second invention of the present application, the above-mentioned first
In addition to the effects of the invention, based on the mounting position of the headlight (left and right, height from the ground) notified using a switch means, a pass/fail judgment is made on the processing result by a microcomputer according to the mounting position. becomes possible.

As described above, the present invention has great effects compared to conventional devices of this type, and is unique as an optical axis detection device for an automobile headlamp.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an example of a conventional headlight tester for inspecting the direction of irradiation of automobile lighting, and Figs. 2 and 3 show a 10-meter pattern reduced to a short distance for explaining the present invention. FIG. 4 is a block diagram showing the basic configuration of an embodiment of the optical axis detection device for an automobile headlamp according to the present invention, and FIG. FIG. 2 is a configuration diagram illustrating an example of how to determine an optical axis and how to calculate an optical axis direction angle in a traveling beam for explaining the present invention. HL...Headlamp (headlight), L...Condensing lens, SC ₁ ...Virtual screen, Sm...Light sensor array, _s1 ~ sm...Light level sensor, LA...Light amplifier, LA ₁ ~ LAm ...amplifier, SCN ...scanning section,
AD...Analog-digital converter, MPU...
...Microcomputer, MEM...Memory circuit,
CPU... Central processing unit, IO... Input/output circuit, DP
...display panel, DRV...driver, W...reduced light distribution pattern.

Claims (1)

[Scope of Claims] 1. A light distribution pattern reduction means for reducing the light distribution pattern to be similar, and a plurality of light amounts for collecting light amount data from the reduced light distribution pattern obtained by the light distribution pattern reduction means. A row of optical sensors in which sensors are arranged at regular intervals on a straight line, each amplifier that amplifies the light amount signal obtained from each light amount sensor in this row of optical sensors, and multiple amplified light amount signals from each amplifier are time-divided. a scanning section that transmits the signal, an analog-to-digital converter that converts the amplified light quantity signal sent from the scanning section into a digital quantity, and
a microcomputer having a memory circuit for storing the output of the digital converter; a display means for displaying the processing results of the microcomputer; and a photosensor array drive for moving the optical sensor array with respect to the reduced light distribution pattern. means for measuring the light intensity at a large number of points over the entire surface of the reduced light distribution pattern by moving the optical sensor array, and transmitting the light intensity data obtained by this measurement to the microcomputer. By processing with
An optical axis detection device for an automobile headlamp, characterized in that the irradiation direction of the headlamp is determined and the optical axis thereof is detected. 2. A light distribution pattern reduction means for reducing the light distribution pattern to a similar extent, and a plurality of light intensity sensors fixed on a straight line in order to collect light intensity data from the reduced light distribution pattern obtained by the light distribution pattern reduction means. A row of optical sensors arranged at intervals, each amplifier that amplifies the light amount signal obtained from each light amount sensor of this row of optical sensors, and a scanning section that time-divisionally sends a plurality of amplified light amount signals from each amplifier. , an analog-to-digital converter that converts the amplified light amount signal sent from this scanning section into a digital amount, and this analog-to-digital converter.
a microcomputer having a memory circuit for storing the output of the digital converter; a display means for displaying the processing results of the microcomputer; and a photosensor array drive for moving the optical sensor array with respect to the reduced light distribution pattern. a first switch means for instructing the microcomputer to start its processing operation; a second switch means for informing the microcomputer whether the headlight is left or right; and third switch means for transmitting the height from the ground of the light sensor, and measures the light intensity at a large number of points over the entire surface of the reduced light distribution pattern by moving the light sensor array. An automobile headlamp characterized in that the irradiation direction of the headlamp is determined by processing the light amount data obtained by the microcomputer with the microcomputer, and the optical axis thereof is detected. Optical axis detection device.